What is the device in question that you are using if I may ask?
Start with only allowing 11Mbps first, see if it connects.
If not then go down to 5.5, see if it connects.
If not then go to 2 and see if it connects.
If you can get it to connect a higher data rates (5 or 11 etc) the better. Otherwise there is a good amount of overhead SSID wise when you enable DSSS-only rates (1 or 2Mbps)